Small-signal modelling and analysis of wind turbine with direct drive permanent magnet synchronous generator connected to power grid

For studying the stability of wind turbine with direct drive permanent magnet synchronous generator connected to power grid after suffering a small disturbance and effectively designing the controllers´ parameters, a complete small signal model of the system is built. By means of eigenvalue analysis, the relation between the modes and state variables can be discovered. Then, the influences of the controllers´ parameters on the traces of eigenvalues are analysed, which helps to design controllers´ parameters. A simulation model of the system based on MATLAB/SIMULINK is presented. The simulation results show that the system is stable after suffering small disturbance of a wind velocity step down and a step up, and the system dynamic responses are consistent with the result of small-signal analysis.